The objective of this study is to determine whether artificial lights have any biological effects. The effect of three different fluorescent lighting systems (simulated daylight, coolwhite, pink) on the C3H mouse are being studied. The parameters measured include longevity, tumor incidence, reproduction (litter size, sex ratio etc.), pathology and behavior. Results to date indicate that 50% of the bred females survived for 46 weeks, 50 weeks and 56 weeks in the daylight, pink and cool white exposed groups, respectively. Data on reproduction and pathology are still being evaluated.